Checked Exceptions

Checked Exceptions are a type of exception in Java that are required to be handled by the programmer. This means that the programmer must either catch the exception and handle it, or declare the method as throwing the exception. Checked Exceptions are used to indicate errors that are likely to occur at runtime and that the programmer should be aware of. Some examples of Checked Exceptions include file not found exceptions, input/output exceptions, and SQL exceptions.

Difference between Checked and Unchecked Exceptions

The main difference between Checked and Unchecked Exceptions is that Checked Exceptions are required to be handled by the programmer, while Unchecked Exceptions are not. Unchecked Exceptions are typically used to indicate errors that are not likely to occur at runtime, or that the programmer cannot reasonably be expected to handle. Some examples of Unchecked Exceptions include null pointer exceptions, array index out of bounds exceptions, and arithmetic exceptions.

Benefits of Using Checked Exceptions

There are several benefits to using Checked Exceptions:

• Improved code readability: By requiring the programmer to handle Checked Exceptions, the code becomes more readable and easier to understand. The programmer can see at a glance which methods can throw Checked Exceptions, and they can take appropriate steps to handle them.
• Improved code reliability: By handling Checked Exceptions, the programmer can prevent the program from crashing. This makes the code more reliable and less likely to cause problems for users.
• Improved code maintainability: By separating Checked Exceptions from Unchecked Exceptions, the programmer can more easily maintain the code. The programmer can focus on handling Checked Exceptions, which are more likely to occur at runtime, and leave the Unchecked Exceptions to be handled by the JVM.

How to Handle Checked Exceptions

There are two ways to handle Checked Exceptions:

• Catch the exception: The programmer can catch the exception using a try/catch block. This allows the programmer to handle the exception and prevent the program from crashing.
• Declare the method as throwing the exception: The programmer can declare the method as throwing the exception using the throws keyword. This tells the compiler that the method can throw the exception, and it is the responsibility of the caller to handle it.

When to Use Checked Exceptions

Checked Exceptions should be used when the error is likely to occur at runtime and the programmer should be aware of it. For example, a file not found exception should be used when the program attempts to open a file that does not exist. An input/output exception should be used when the program attempts to read from or write to a file that is not accessible. A SQL exception should be used when the program attempts to execute a SQL statement that is invalid.

When Not to Use Checked Exceptions

Checked Exceptions should not be used when the error is not likely to occur at runtime, or when the programmer cannot reasonably be expected to handle it. For example, a null pointer exception should not be used when the program attempts to access a variable that has not been initialized. An array index out of bounds exception should not be used when the program attempts to access an element of an array that is out of bounds. An arithmetic exception should not be used when the program attempts to perform an arithmetic operation that is invalid.

Online Courses on Checked Exceptions

There are many online courses that can help you learn about Checked Exceptions. These courses can teach you the basics of Checked Exceptions, how to handle them, and when to use them. Some of the most popular online courses on Checked Exceptions include:

• Exception Handling in Java SE: This course from Oracle teaches you the basics of exception handling in Java, including how to use Checked Exceptions.
• Exception Handling in Java (Java SE 11 Developer Certification 1Z0-819): This course from Oracle prepares you for the Java SE 11 Developer Certification exam, which includes a section on exception handling.
• Handling Exceptions (Java SE 8 Programmer I Certification 1Z0-808): This course from Oracle prepares you for the Java SE 8 Programmer I Certification exam, which includes a section on exception handling.

Conclusion

Checked Exceptions are an important part of Java programming. They can help you improve the readability, reliability, and maintainability of your code. By understanding how to use Checked Exceptions, you can write code that is more robust and less likely to crash.